Commit graph

9 commits

Author SHA1 Message Date
Michał Kępień
ec7967cfaf merge-base, xdiff: zero out xpparam_t structures
xpparam_t structures are usually zero-initialized before their specific
fields are assigned to, but there are three locations in the tree where
that does not happen.  Add the missing memset() calls in order to make
initialization of xpparam_t structures consistent tree-wide and to
prevent stack garbage from being used as field values.

Signed-off-by: Michał Kępień <michal@isc.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-20 12:53:26 -07:00
Carlo Marcelo Arenas Belón
81ed2b405c xdiff: remove duplicate headers from xpatience.c
92b7de93fb (Implement the patience diff algorithm, 2009-01-07) added them
but were already part of xinclude.h

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-28 21:51:22 -07:00
Jonathan Tan
2477ab2ea8 diff: support anchoring line(s)
Teach diff a new algorithm, one that attempts to prevent user-specified
lines from appearing as a deletion or addition in the end result. The
end user can use this by specifying "--anchored=<text>" one or more
times when using Git commands like "diff" and "show".

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-28 10:40:04 +09:00
Todd Zullinger
484257925f Replace Free Software Foundation address in license notices
The mailing address for the FSF has changed over the years.  Rather than
updating the address across all files, refer readers to gnu.org, as the
GNU GPL documentation now suggests for license notices.  The mailing
address is retained in the full license files (COPYING and LGPL-2.1).

The old address is still present in t/diff-lib/COPYING.  This is
intentional, as the file is used in tests and the contents are not
expected to change.

Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-09 13:21:21 +09:00
Derrick Stolee
19716b21a4 cleanup: fix possible overflow errors in binary search
A common mistake when writing binary search is to allow possible
integer overflow by using the simple average:

	mid = (min + max) / 2;

Instead, use the overflow-safe version:

	mid = min + (max - min) / 2;

This translation is safe since the operation occurs inside a loop
conditioned on "min < max". The included changes were found using
the following git grep:

	git grep '/ *2;' '*.c'

Making this cleanup will prevent future review friction when a new
binary search is contructed based on existing code.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-10 08:57:24 +09:00
Johannes Schindelin
044fb190f7 diff: fix a double off-by-one with --ignore-space-at-eol
When comparing two lines, ignoring any whitespace at the end, we first
try to match as many bytes as possible and break out of the loop only
upon mismatch, to let the remainder be handled by the code shared with
the other whitespace-ignoring code paths.

When comparing the bytes, however, we incremented the counters always,
even if the bytes did not match. And because we fall through to  the
space-at-eol handling at that point, it is as if that mismatch never
happened.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-11 11:55:53 -07:00
Junio C Hamano
307ab20b33 xdiff: PATIENCE/HISTOGRAM are not independent option bits
Because the default Myers, patience and histogram algorithms cannot be in
effect at the same time, XDL_PATIENCE_DIFF and XDL_HISTOGRAM_DIFF are not
independent bits.  Instead of wasting one bit per algorithm, define a few
macros to access the few bits they occupy and update the code that access
them.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-02-19 15:36:55 -08:00
Tay Ray Chuan
1d26b252f1 xdiff/xpatience: factor out fall-back-diff function
This is in preparation for the histogram diff algorithm, which will also
re-use much of the code to call the default Meyers diff algorithm.

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-07-07 09:41:24 -07:00
Johannes Schindelin
92b7de93fb Implement the patience diff algorithm
The patience diff algorithm produces slightly more intuitive output
than the classic Myers algorithm, as it does not try to minimize the
number of +/- lines first, but tries to preserve the lines that are
unique.

To this end, it first determines lines that are unique in both files,
then the maximal sequence which preserves the order (relative to both
files) is extracted.

Starting from this initial set of common lines, the rest of the lines
is handled recursively, with Myers' algorithm as a fallback when
the patience algorithm fails (due to no common unique lines).

This patch includes memory leak fixes by Pierre Habouzit.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-07 13:35:44 -08:00